This invention relates generally to catalytic converters having exhaust pipe attachments for attachment to an internal combustion engine and in particular to an improved heat insulating device for such catalytic converters.
During running of an engine driven vehicle, heat developed at an exhaust system, particularly at a catalytic converter unit exposed to a high operating temperature, amounts to such a degree that dry grass and like inflammable materials on a road occasionally burns upon contact with the exhaust system. One conventional solution to this is to mount a heat insulating element beneath the underside of a converter casing or exhaust pipe of the exhaust system, or to enclose those elements in a jacket type heat insulating element.
Such structure however involves several drawbacks: the heat insulating element prevents heat from being dissipated to the outside, therefore the element itself is heated to an elevated temperature; Since the panel directly adjoins to the road surface, water is splashed into a clearance between the outer casing wall of the exhaust system and the heat insulating element rusting their metal parts, and stones or pebbles are liable to be thrown into that clearance causing offensive rattling noises.